1. Field of the Invention
The present invention concerns power saving classes in a wireless network and more particularly, controlling such power saving classes to improve performance of mobile stations.
2. Description of the Related Art
Sleep mode is a state in which a mobile station (MS) conducts pre-negotiated periods of absence from a serving base station (BS) air interface. The Institute of Electrical and Electronics Engineers (IEEE) standard 802.16e defines sleep mode with the intent to minimize MS power use and to decrease the use of serving BS air interface resources. In particular, in the specification of the 802.16e standard, sleep mode operation is implemented in the form of power saving classes (PSC). Each PSC is a group of connections that have common demand properties. Typically, different PSCs will exist for real-time connections—such as voice over Internet protocol (VoIP) or push-to-talk (PTT) communications—and for non-real-time connections—like file transfer protocol (FTP). Moreover, there may even be different PSCs for the real-time connections, depending on the interval between consequent allocations for these connections. As such, an MS may have multiple PSCs in effect at the same time when the MS is simultaneously running a mix of real-time and non-real-time applications.
Because each PSC operates independently on its own sleep/awake schedule, it is only possible for an MS to turn off its transceiver and enter a sleep state when all the PSCs are in a sleep interval. Thus, the opportunities for the transceiver to enter a sleep state are decreased, particularly as the number of PSCs is increased. As a result, the MS suffers from increased power drain and shortened battery life.